SMALLER MAMMALS OF NORTH AMERICA
nests thus safely located they have one litter
containing an average of from four to six, but
sometimes numbering up to twelve, young a
year. They are born at any time from April
to June, according to the latitude. The number
of young in a litter is enough to render weasels
very abundant, but this is rarely the case, and
raises the question as to the influence which
holds their number in check.
They are both nocturnal and diurnal, ap
parently in almost equal degree, since they are
frequently observed hunting in the middle of
the day, while their nocturnal raids on poultry
houses testify to their activities at night. When
hunting they appear like sinister shadows and
are persistent in pursuit. The young commonly
remain with the female until nearly or quite
grown and follow her closely on hunting trips.
It is interesting to see a pack of these deadly
carnivores working, the mother leading and the
young skirmishing on all sides, now spreading
out, now closing in, like a pack of miniature
hounds. On these family hunting parties, how
ever, they usually keep close to the rocks, logs,
brush, or other cover.
Themselves subject to the law of fang and
claw, weasels are killed and eaten by wolves,
coyotes, foxes, and various birds of prey. Their
very lack of fear perhaps in many cases leads
to their destruction.
These representatives of the primitive wood
land life continue to occupy practically all of
their original range. They visit farms in all
parts of the country and I have seen them near
the outskirts of Washington.
It is well that weasels are not abundant, for
beasts with such innate ferocity and love of
killing would otherwise be a menace to the
existence of many useful species of birds and
mammals, especially the game birds. In many
places they live almost entirely on mice, and
there they should be left unmolested; but
whenever they locate in the vicinity of a chicken
yard the owner will do well to take proper
measures for protection.
THE LEAST WEASEL (Mustela rixosus
and its relatives)
(For illustration, see page 452)
In addition to the larger members of the
tribe briefly described in the foregoing sketch,
the true weasels include another group of
species, so small they may appropriately be
termed the dwarfs of their kind. They vary
from a half to less than a fourth the size of
the larger weasels, but have the same char
acteristic form and proportions, except that the
tail is very short and never tipped with black.
Like the larger species, they change their brown
summer coat for white at the beginning of
winter and back again in spring.
The least weasels are also circumpolar in
distribution, but are limited to the northern
parts of Europe, Asia, and North America.
In England and other parts of the Old World
the group is represented by the well-known
species Mustela vulgaris. In North America
several species are known which, between them,
share all the continent from the Arctic coast
south to Nebraska and Pennsylvania. On the
desolate islands extending from the mainland
far toward the Pole their place seems to be
taken by the ermine.
The dwarf weasels appear to be less numer
ous and, as a consequence, less known in most
parts of America than in England and north
ern Europe.
Our most northern species,
Mustela rixosa, sometimes called the "mouse
weasel," occupies Alaska and northern Canada
and has the distinction of being the smallest
known species of carnivore in the world. In
this connection it is interesting to note that
in Alaska we have associated on the same
ground the least weasel and the great brown
bear, the smallest and the largest living car
nivores.
Least weasels are characterized by the same
swift alertness and boldness so marked in the
larger species. In fact they are, if possible,
even quicker in their movements. Once when
camping in spring among scattered snowbanks
on the coast of Bering Sea, I had an excellent
opportunity to witness their almost incredible
quickness. Early in the morning one suddenly
appeared on the margin of a snowbank within
a few feet, and after craning its neck one way
and the other, as though to get a better view
of me, it vanished, and then appeared so
abruptly on a snowbank three or four yards
away that it was almost impossible to follow
it with the eye. It was beginning to take on
its summer coat of brown and was extremely
difficult to locate amid the scattered patches
of snow and bare moss of the tundra. Cer
tainly no other mammal can have such flash
like powers of movement.
They feed mainly on mice, lemmings, shrews,
small birds, their eggs and young, and insects.
Mice furnish a large proportion of their prey
and weasels have often been seen following the
runways of field mice. Their small size enables
them to pursue mice into their underground
workings as readily as a ferret enters a rabbit
burrow. They also climb trees and bushes with
great agility, although nearly always seeking
their victims on the ground. The mice upon
which they prey are often so much larger than
the weasels that they cannot be dragged into
the dens. The weasels continue in full activity
throughout the winter and constantly burrow
into the snow in search of their prey. In the
snow or in the ground the holes of this animal
are about the diameter of one's finger.
In the Old World the small weasels are re
ported to have several litters in a season, each
containing five or six young. At Point Barrow,
Alaska, a female captured on June 12 still con
tained twelve embryos.
This indicates that
only one litter a year would be born there, and
that Mustela rixosa is more prolific than its
European representative.
In the more southern latitude least weasels
live in forests and about farms, sheltering
themselves under logs, brush piles, stone walls,
471